Carbonization of carbonizable solids



Patented May 6, 1952 UNITED STATES PATENT OFFICE CARBON IZABLE S WilliamW. Odell, Washington, 1 0., and George .L.:Matheson, Union, N. J.,assignors'to Stand- ,ard Oil Development. Company, a corporation ofDelaware Application June 14, 1947, Serial -No. 7 5 fl';62 3

:Qiaims. (Cl. L292.6)

This invention relates tos-the.carbonizationof solid fuels. It has to dowithzthe carbonization of solidcarhonizable materials :by subjectingthem to an elevated "temperature while in a fine state of subdivision.More specifically it relates ,to the :carbonization of finely dividedsolid fuels and the production therefromof finelymdivided carbonizedsolids :by. passi'ng the said finely :di-

vided fuelas alstream while lconfinedwin :a ncarbonizer downwardlythrough .a :hot zone .ata controlled raterwhile promoting combustion insaid zoneincontact with said solidsandwhile passing a gasiform :streamupwardly sthrough said downwardly :fiowing fuel lsolids :.at. -suc h .a

. velocity that therparticlesvof. solidfuel in process are maintained asa fluidized state in said rear bonizer. The invention relates to both.process and apparatus vvherebytthe finely dividedsolid iuel preparedfoiflcarbonization is .in part doashed prior-to its passage through thehot zone.

- In ordinary practice in carbonizing solid. fuels, the employment ofvery finely divided fuels-:is avoided-usually because a stationary bedof .such solids iorms a heat.insulatingsmass.rvhichresults in prolongedduration of the-timelofucare ,boniz'ing. So-tar ets -we are aware :ithas inot been economical .to treat finely divided solids "for thepurpose of making,..a;finely' divided .carbonizedfsolid residue.vOur:experiments-show that a solid fuelcan beeconomically-carbonized:irna

fine state aof subdivision. provided :meansare supplied for fluidizingit landv:,passing-;ait LiIlFJthB fluidized :state in countercurrent:direction and in.contactwithmpwardly flowing :hotgases. :It

has also been i'ounddesirableto control the temperature'dn :therhotzonelof the fluidized fuel in :the; processand :to. :;control its rate=of=trave1 through theshotszone, vasawell-as :to .control,:ithe nature'of the hottgaseswwith =which ittiscontacted during processing.

..One 'Ejo'f. the, objects; of. this ;inyention is, to carbonizefine1y:;divided. solid, carbonizableziuels rapidly. Another object isto:control the dura- :tion .of. :the .zcarbonizing time, the temperatureoiparbonization;xandathenature;ofcthmfiuidizing .gas, :streams.1emp1oyed sci-that.athexxproductuof .car'bonizationzis :hig'hly.weactive; and-:may: :be

nailed van activated .carbon. Another objectuis ;to recover gaseous.:and .yaporous:pmductsirom ;-the carbonization ;o,f {finely divided:tsolid :fiuel. still another-object vis ;.the::-reduction;of-, theashcontent ,of the :fuel; prior :toits :carbonization.

.Anothermbiect 15.2120 provide apparatus. inawhich the. aforementioned.obiects icansbe. accomplished economically. ".sstill other :obj ects.will; ;become .2 apparent from the disclosures hereinafter made. In the,,carbonization of goal, it necessary :to take into consideration thecondition ofthe coal other than: its state of ,fineness. Thecoal rankand amount of exposure of the coal to the atmosphere have much to dowith coking properties of coal. Considerations.- are given to thesefactors in the operation of the process of this invention. It is wellknown that lignite. sub-bituminous coal, and certain bituminousc0als'do-no t have strong coking properties and. therefore, they can bereadily carbonized in a fine state of division without appreciableagglomeration or building up of large size pieces by cementation.However when coals having, strong coking properties are ground to. finesizes and are directly carbonized by exposure to heat, the coal passesthrough a plastic state .at a temperature of aDDroximatelyBOU .toiifii)?F, andv it is-necessary in order to obtain an end product, which is alsoin a line state of sub-division, to-prevent thev a glomerationofparticles or to reduceuagglomerating action to. a minimum. We find thatthis can bestbe done when the par.- ticles .of coal in process aremaintainedin the fluidized, condition during the heating period andparticularly during. that period in which they pass through the plasticrangeoftemperature; By maintaining particles during carbonization invibrant or ebullient. motion, itais found ,that .carbonizat-ion can .beso conducted thata-the solid residue isin a nnestate of s}1h..-division. Qur tests:also-.revealthatitis desir ble to i a n th a cl s osolid. fuel in yiolent state of ebullient :mot n inthe presence 0 =smilars lid$ whichnha e ready. een pe boniZfid, .zyvhile they passthrough the plastic range of vtemperature. -When carbonization has once,taken place at. the chosen-temperature, say f ex WW @292 E ac ivatin-1:15 pr m e y as n s eamtth ouehct flu d i d bon d m ssusacti a ingandcqolin simultaneously. Means ior accon plishinga-these ends arevprovided in this invention .as will be- .come evident by reference, tothe; .iigure.

The single figure .in the-,acompanyingjdrawing is a diagrammatic,elevationjof Zone ior.m. of apparatus which can be i used ;in,thecarbonization In the; figure the carbonizer i confines abed of fluidizedsolids having. a :top level L and it has packed zones 2 and 3, whichzones containnon fluidized solids .of much-larger =siz than -the;par

ticles of fuel to be treated and which solids form a porous bed or mat,the interstices of which are channels for the passage of the finelydivided particles of fuel downwardly therethrough and for the upwardpassage of gases therethrough. The carbonizer has a porous support l forthe bed of fluidized solids, an outlet 5 with control valve 6 for thedischarge of the fluidizing stream, and a dust separator 1.

Located adjacent to the top of the carbonizer I and connected thereto isa de-ashing unit I8. This unit is preferably identical in constructionand mode of operation with that described in our co-pending applicationSerial No. 726,530, filed February 5, 1947, now abandoned and entitledProcess and Apparatus for Separating Mixed Materials." A similar systemis described and claimed for the production of activated carbon in ourcopending application Serial No. 754,624, filed June 14, 1947, andentitled Processing Carbonaceous Solids. For the purpose of thisdescription it is sufficient to note that near its lower end, thede-ashing unit is provided with a porous grid or grate II below which isan inlet line controlled by valve 24 for introducing a fluidized gaswhich may be air or combustion gas or any othergas which is preferablynot reactive with the solid material treated in this zone. The de-ashingunit is operated so as to maintain therein a level of fluidized solidLI, which is sufficiently high to cause the solid to overflow into thedrawofl line 28 controlled by valve 29. This drawoff line terminates inthe carbonizer I below the level L of the fluidized solid therein.

At the upper end, the de-ashing unit is provided with a line I2 forleading off the fluidizing gas. The flow of this line is controlled by avalve I3. Connected with line I2 is branch line I5 which may be used toconduct the fluidizing gas, where it is air, oxygen or other combustionsupporting gas, to bustle pipe I6 which is connected to the carbonizer Ibetween zones 2 and 3. The flow of gas in branch line I5 is controlledby valve I4. At an intermediate point the de-ashing unit is providedwith inlet line 34 controlled by valve 33 through which the finelydivided solid fuel to be treated is introduced into the unit. At itslower end, above the grid II the unit has a drawofi line 26 controlledby valve 21 for withdrawing ash from the unit.

' When reference is made to ash in connection with this de-ashing unit,there is contemplated those non-fuel materials with which the fuelmatter is contaminated such as quartz, sand, shale, gypsum, pyrites andother mineral matter. This ash has a density greater than the fuelmaterial whereby when the de-ashing unit is operated in'accordance withthe teachings of our aforesaid'application, a fairly complete separationof the fuel constituents from the ash can be "realized with the fuelconstituents leaving the unit near the top thereof and the ash leavingthe unit from its bottom portion. 1

- Combustion supportinggas, which may be air, is supplied throughconduit I8 and valve l9 to the combustion zone I! of the carbonizer,whereas said combustion supporting gas is supplied when desired alsothrough conduit 20, valve 2I and inlet 23 to the base of the carbonizer.Steam is'introduced through valve 22 and intake 23. Means forwithdrawing the treated solids, namely the carbonized finely dividedsolids, from the carbonizer, are indicated by offtake 3| and valve 32.Auxiliary means of supplying a gasiform stream to the carbonizer at anupper zone thereof is shown by conduit 9 and valve 8; the stream may bea combustion supporting fluid, steam, gas such as recycle gas, mixturesthereof, or other gaseous material, according to effect desired.

Referring to the figure, the operation, in general, is as follows:Finely divided solid fuel to be treated is charged into a middle portionof the re-ashing unit I0 through valve 33 and conduit 34 at a rateadapted to maintain the bed level LI in saidv unit. Air or otherfluidizing gas is introduced through 24 and passes through porous memberII, fluidizing the finely divided fuel in III, the gas stream passingout through I2, at least a portion of it being conducted through valveI4 and conduit I5 to carbonizer I, whereas the remainder, if any, isdischarged through valve I3. The fuel thus fluidized in I0 separatesfrom a portion of its ash content, the ash passing out through ofitake26 and valve 21, whereas the de-ashed fuel is discharged substantiallycontinuously through offtake 28 and valve 29 to the carbonizer I.

Steam is introduced into carbonizer I through valve 22 and conduit 23,and combustionis pro-. moted in the hot zone I1, after some of the fuelin this zone is ignited, by virtue of combustion supporting gas suppliedthrough bustle pipe I6 to said hot zone. Valve 32 is opened sufficientlyto. allow treated solids to pass out of carbonizer I through offtake 3|at a predetermined rate. The products of the combustion promoted in hotzone I'I, along with the gases resulting from passing steam up throughthe fluidized solids in the portion of the carbonizer below the hotzone, pass upwardly-through the packed zone 2 and the upper fluidizedzone A at such a rate that the particles of said fuel are maintained invibrant or ebullient motion throughout the bed. Some of the heatgenerated by the combustion in zone I! is imparted to the downwardlymoving fluidized solid fuel of which the bed is comprised.

After operations are underway, it will be found that the steam enteringthrough intake 23 absorbs heat from the solid fuel in the lower portionof the fluidized solids in carbonizer I and to some extent in coolingthe carbonized product it reacts therewith forming hydrogen and carbonoxides, which gases further react in the combustion zone I1. Thus thefinely divided solid fuel is heated to a temperature above the plasticrange in the upper portion of the bed in carbonizer I and it then passesthrough a hotter zone in contact with the non-fluidized solids 2 andfinally through the hottest zone I! of the bed wherein it reaches thechosen maximum temperature and then passes through packed zone 3 andzone C which are the steaming and activating zones, discharging asdescribed through 3i and 32.

Thermocouples indicated by 38 and 39 are employed to aid in regulationof the operation. Sufficient combustion is promoted in combustion zoneI! so that the gas stream passing up through the packed zone 2 andthrough the upper fluidized portion of the bed in zone A, has atemperature sufiiciently high to heat the fluidized particles in zone Ato a temperature above the plastic limit so that clogging will not occuras these particles are drawn downwardly into the packed zone 2. Since itis usually desirable to maintain a given maximum temperature in thecombustion zone Il, it is sometimes desirable to recirculate products ofcombustion or other diluent gasiformstream with the air supplied tocarbonizer I through lfi inorder to prevent-en cessively -'high"temperature in'zone IT and in order to furnish a-suflicient volume ofhot-gas to accomplish the-desired fiuidizingand heating eiiect in zoneA.

Inma-king-active carbon, it isusually desirable thatthe particles of thecarbonizable material treatedbe heated suddenly to a temperature of theorder -of 900 to about 1 200 F., and thatthe product resulting from thisheating-be subsequently heated to a higher 'temperatureandsubsequently-steamed All of these are acccmplished-in the :operation ofthe carbonizer l of the=iigure=as described. The hot particlespassingfromzone llrdownwardly through thepacked zone 3,-contact steam risingthrough zones land 3 and form a given .amount of water gas, which gasrisburned in zone -I 7. Thus. a iportionof :the heat required forconducting.the'process is furnished iby -theu'steaming whichis: essential makingactivatedcarbon. .The operation, with modifications .to suit specialconditions, is 'applicable to theproduction of bone black. from crushedbones, to thev production of. a .carbonized fuel suitableior :use, in.makingbriquettes or in mixtunes with coking coal for coke-oven use and.for otherwisettreating materials whichrequire heating to .elevatedtemperatures and cooling.

example of :the production of. activated. carbon with yieldsobtained inasparticular caseare given :as .follows: Raw, lignite. is .usedas theraw material and-it is: crushed .to. a .size of .20. mesh with.tsomersmaller. sizes. .11. is .then passed through ;an ash separator.as shown at 18 .in .the figure, sand the ash. content. is reduced.During this .-.de-xashing.t.the lignite. is dried by passing .hot gases.upi throughrthede-ashing .unit. The warm partlyJde-ashed lignite in afinestateof division is substantially.continuously discharged from theunit I through ofitake 28 and valve 29 to :the.

carbonizer I into theifluidized bed of similar but hot partly carbonizediignite, which bed is at a temperature 01 .1200 F. This temperature ismaintainedintheupper zone. A. Meanwhile the volatile: matter/and tarryvapors are discharged from above thehedthroughseparator l, offtake am!.valve 6. .gThe tarry vapors are condensed andz-separated-by known.means.

The solid particles of .lignite are carbonized in the fluidized state.and. are substantially continuouslyxpasseddownwardly from the :top zone:of thefbed'tto.isubstantially the bottom zone of the bed, inamely; from.zone A :to zone C. Combustionsismromoted in ;a:.middle zone ll. of the.car-

bonizer; :whereby'tthe. temperature is "maintained thereinat;.J.-4'Z0;to.:1650 F... Thecombustion is promotedxin: zone I l 1 bypassing .the air :used for .fluidizingzzthe solids in .de-zashing unitit? back through valve I4, conduit I5 and .bustle pipe it intothecarbonizer l. Throughout this operationsteam is introduced frombeneath grid 4 through cvalve 22 and inlet 23. The solidsresultingrirom.carbonization, which under these conditions is an-activecarbon, is withdrawn substantially continuously through 'offtake 3i andvalve :32.

The-temperature inthe upper "zone A of the fluidized bed in thecarbonizer l preferably should be in therange 1000 to 1250 F. for theproduction Iof-carbon'for'use in removing sulfur froin'gases forexample. The amount of combustion promoted in zone 11 is that which willprouidethe desired temperature in the upper zone hand at the same timeraise the temperawture'of'tlieparticlespassing through. I 1 tea temperature oi the order-10f "1450 "to 1'850' 'iE.xusua1iy.

The steampassingxthrough 22' and ..2:3 partly.

coolsthe 'carbon'in zones 3 *andJC, andsimnltaneously generates gas by.the. .waterigas reaction. The gas stream introduced into-lthe:car-

bonizer through pipe i6 is thexmajor 'fluidizingstream component,whereas in 1 the lower portion of the bed, namelyinzones 3 and .C.thesteamsisthe major fluidizing reactant.v :For the purpose of fineadjustment of temperature. someair can.

at will be introduced along withthe. steam. by opening valve 2| to e.desired extent Likewise other'fluidizing medium than the circulating.gas

can be introduced through 16. by :openingravalve l9.

The "raw l-ignite treated as above has-a :composition substantiallyasrfollows:

" f Percent by weight B. t. u. per pound i 7310 The composition after(drying. and .de-ashing;

The ash removed perton of raw coal 'used was 88 pounds or 52.3 per centof. the ash originally present. The partly carbonized lignite as itleaves zone A and passes into the packed portion, zone 2, is largelycarbon with 5 to 7 per cent of volatile matter, the remainder being ash.The yield at this point is a little more than'35 per cent of the totalraw lignite treated. The calorific value is about 12,600 B. t. u. perpound. The tar evolved amounts to "about 5.6gallons 'per ton of raw coaltreated. The specificgravity of the tar is about 0.98. The approximategas yield perton of raw lignite'treated atthis parf ticular temperature,and separately determined, without dilution with other gases, is about4470 cubic feet.- The 'yield of activated-carbon after passing throughzones Band Cis approximately 29 per cent of the original ligniteused.

The-properties-qf carbon-made inthisima-nner vary according-to" thenature of the raw material initially cha-rged to the "rate of 'heatingof the upperzone A, 'to'the final temperature attained in the hot/zonel1, and to-the --amount of steaming, as wellasithe temperature of thesteam introduced through valve 22 and intake -23. These variables canbeadjusted-to suit-anypar ticular case.

It is essentialthat the particles 'of :lignite-in' process besufficiently fluidized so-that they-=will mix and will fiow downwardlythrough the packed zones as described. The factors relatingtovelom'ity'of' flow for given size particlesis now-well known in the art butfor the purpose of 'OIELI' -f ness'it may be stated thatwith particleshaving sizes as given in the foregoing example,-the

velocity of the fluidizing stream-as it leaves the,

bed of fluidized solids in carbonizer l should' be approximately 0.4 to1.0 feet per second; finer size solids do not require as high avelocity-of the *fluidizing stream as large s'ize particles.

it is important that the size of the packing in zones .2 and 3 besufficiently large so that the interstices are large enough for theparticles of solids being treated to be fluidized therein and flowdownwardly therethrough.

It will be understood that the temperature in zone I! may be controlledto suit conditions and may be as high as 2200 F., although it iscommonly within a range of 1400 to 1800" F. It is also understood thatthe steam may be superheated as the occasion requires.

It is further understood that the gases removed through ofitake 5 andvalve 6 from the carbonizer may .be used, after removing condensiblematter therefrom, as fuel, and supplied to zone l I by means .not shown,or through conduit l8 and valve l9 when so-desired. Similarly the lattergas or gas passing out through valve [3 may also be introduced with thesteam beneath grid 4 when desired.

When using strongly coking coals as the raw material to be carbonized,it has been found that the introduction of an auxiliary heating fluid inzone A of the bed above the packed zone 2 is sometimes beneficial. Thisnot only has the effect of decreasing the bed density in zone'A but itpermits the introduction of some oxygen, which may be in the form ofair, with or without steam or recirculated gas; its use facilitates theheating of the particles in zone A and minimizes any tendency forparticle agglomeration, although it does tend to reduce the amount ofreadily recoverable tar produced. When it is desirable to increasecapacity to the maximum, air can be thus introduced through valve 8 andconduit 9, or air with recirculated hot gas may be used with steam asdesired.

. Other modifications of operating procedurev may be conceived withinthe scope of this invention and likewise novel effects may be producedby a different arrangement of packing zones than those shown in thefigure. A greater number of packed zones than two may be employed andthe packing material used may be spheres, Berl saddles, or other shapedmaterial which will resist exposure to heat and which will furnishsatisfactory interstitial space for the flow of particles in processtherethrough. The dura tion of the time of exposure of the carbonizedparticles in zones (land C to the action of steam is controllable bycontrolling the size of they chamber confining these zones, particularlythe depth.

Referring to the figure, operating adjustments are made, after the ratesof flowof feed-of fresh solids, discharge of treated solids and supplyof fiuidizing medium are once set, as follows: To increase thecompleteness ofcarbonization of the solids flowing into zone B from zone2 either decrease the rate of feed of solids by adjusting valve 29 andsimilarly adjusting valve 32, or increase the circulation of gases tothe combustion zone by more completely closing valve i3 and openingvalve 16 more fully, or by introducing an additional amount ofcombustion supporting gas by opening valve I9, or by combinations ofthese adjustments, or by heating the raw fuel in it) to a highertemperature bypromoting combustion reactions therein using more oxygenintroduced through 24. Another adjustment for accomplishing a similarresult is to supply a combustion supporting gas by opening valve 8. Todecrease the completeness of carbonization of the solids at about thebottom of zone 2 the opposite adjustments are made. 1

In case the temperature of the solids being and the flow of solids inprocess regulated ac-- cording thereto or the flow of fluids,particularly the combustion supporting fluids should be adjusted inaccordance therewith. I

For fiuidizing solids varying from very finesize in one case to verycoarse in another case, the velocity of the fiuidizing gas streammeasured as in an empty carbonizer will vary respectively from about 0.1to 10.0 feet per second. The velocity referred to at this point, and atother points in the specification, is superficial velocity; that is, thevelocity which would obtain in the enlarged zone or reactor with a giveninlet and outlet velocity if the enlarged zone or reactor were empty.When operating at low carbonizer capacity it is sometimes necessary touse an appreciable amount of recirculated gas and only a small amount ofcombustion supporting gas. In this case gas passing out of thecarbonizer through 5 and 6 is recirculated back to the carbonizerpreferably after removing condensable product; it is compressed to thenecessary pressure and is supplied through valve 31. Actually verylittle heat is required, when the fuel is sup-,-

plied dry, in addition to that carried away as.

sensible heat in the gas and solids, and it is pose-r sible to reducethese losses to small quantities. For example when zones C and 3 aredeep, the solids may be discharged cool and steam at about 250 F. may beused. This effect is further facilitated by employing a deep zone C andincorporating another packed zone in it but spaced below zone 3.

Normally the pressure in the system is just sufficiently aboveatmospheric pressure to operate as described but with some carbonaceoussolids the physical nature, porosity, density, etc. are appreciablyaffected by a change in pressure; hence this invention is not limited inthis respect it may be operated at high or low pressures. The density ofthe product made at high pressure is greater than that made at lowpressures.

Referring again to the figure, the zones Cand 3 are shown to havesmaller diameter than A and B but this is not always necessary. Thediameter is proportioned so that the velocity of the stream flow willfiuidize the solids in zones C and 3. Because the volume of gaseousfluids flowing upwardly is greater in zones A and B than that in C and 3it is advisable that the latter zones be of smaller diameter than theformer zones, in order to obtain best results.

The actual time required to carbonize a fuel when the particles are say60 to 200 mesh size is a variable depending on the moisture content ofthe fuel, volatile matter initially present therein and its temperatureas charged as well as the velocity of flow and temperature of the gasespassing upwardly through the bed. With a temperature of 1200 F. in zoneA coal can be carbonized in zones A and 2 in a matter of seconds, 10 to30 seconds being usually ample. However, operating variables may beadjusted to provide longer or shorter time when desired. A conven ientrate of supply of dry coal to carbonizer l for carbonizing is 0.05 to0.25 pounds per second per square foot of horizontal sectional area ofzone A, varying with the depth of zone A and the temperature of the gasstream rising from zone 2 into zone A and the velocity of said stream.The overall duration of the carbonizing time (total time in thecarbonizer) may be adjusted at will. Normally a convenient time is ofthe order of 20 to 60 seconds.

It will of course be understood that the carbonizer can be operatedwithout the de-ashing unit when desired. In this event either chamber l0can be considered as a reservoir or the feed for the fuel carbonizer cancome directly from conduit 34 and through valve 33. In this caseconsider valve I4 closed and the gases for zone I! are supplied throughvalves l9 and 31.

One skilled in the art will recognize that the procedures outlinedherein and modifications of them will be applicable in makinglow-temperature coke, high-temperature coke, in the pyrolysis of oilshale, and in general in heat-treating finely divided solidsparticularly carbonaceous solids. Magnesium carbonate gives up CO2 at350 C. and calcium carbonate decomposes at 825 0.; these products may becalcined, in a fine state of division in this manner. In this case airwould be used as the bottom fiuidizing agent and coolant and it would bepreheated in traveling up through zones C and 3 and would be thecombustion supporting fiuid in zone 11, the fuel could be introducedthrough valve 31.

Having described our invention so that one skilled in the art canpractice it, either as described or with modifications, we claim:

1. The continuous process of carbonizing carbonizable solids whichcomprises forming a deep single substantially continuous downwardlymoving bed of finely divided carbonized solid fuel in an uprightcarbonizer, continuously feeding the carbonizable solid in finelydivided state to the upper part of said bed, maintaining said bed in afluidized, condition by passing upwardly therethrough a stream of gascomprising, near the lower part of said bed, steam introduced at thatpoint and, at a higher level in said bed, steam, combustion supportinggas and gaseous combustion residues, causing said bed in its downwardtravel to pass through the interstices of large size bodies maintainedas a pack in two separate zones in the path of said bed, said packspreventing back-mixing of the finely divided solid upwardly through saidzones into preceding portions of saidbed..introducing the combustionsupporting gas into said bed between said zones, recovering from abovesaid bed vaporous products of the carbonization of said carbonizablesolid and recovering carbonized solid from the lower por-- tion of saidbed below the point of introduction of steam into said bed, the flow ofmaterials and the feed of steam and combustion supporting gases being soregulated that throughout the upper portion of the bed above the upperpacked zone, the finely divided material is maintained at acarbonization temperature above the plastic range of said carbonizablesolid and between 900-1400 E, in the next lower zone including the upperpacked zone, the finely divided material is maintained at a temperaturebetween about 1600-2000 F., and in the lowermost zone, including thelower packed zone, said material is quenched with steam.

2. In the process defined in claim 1, the step of introducing a smallamount of a combustion supporting gas along with the steam.

3. The process as defined in claim 1, in which the solids are fuelselected from the class consisting of lignite, sub-bituminous coal,bituminous coal, semi-bituminous coal, and anthracite coal.

4. A method according to claim 1 in which the finely dividedcarbonizable solid fed to the carbonizing zone is subjected to apreliminary treatment for the removal therefrom of ash constituents.

5. A method according to claim 1 in which the combustion in said nextlower zone is at least in part the combustion of combustible gasesproduced by the reaction between steam and hot carbon in the quenchingzone.

WILLIAM W. ODELL., GEORGE L. MATHESON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,639,356 Wallace Aug. 16, 19271,923,918 Davis Aug. 22, 1933 1,927,459 Krczil Sept. 19, 1933 1,955,025Salbel et al Apr. 17, 1934 2,148,827 McFarland Feb. 28, 1939 2,162,763Stuart June 20, 1939 2,444,990 Hemminger July 13, 1948 OTHER REFERENCESBureau of Mines R. 1., 3,711, May, 1943. l

1. THE CONTINUOUS PROCESS OF CARBONIZING CARBONIZABLE SOLIDS WHICHCOMPRISES FORMING A DEEP SINGLE SUBSTANTIALLY CONTINUOUS DOWNWARDLYMOVING BED OF FINELY DIVIDED CARBONIZED SOLID FUEL IN AN UPRIGHTCARBONIZER, CONTINUOUSLY FEEDING THE CARBONIZABLE SOLID IN FINELYDIVIDED STATE TO THE UPPER PART OF SAID BED, MAINTAINING SAID BED IN AFLUIDIZED CONDITION BY PASSING UPWARDLY THERETHROUGH A STREAM OF GASCOMPRISING, NEAR THE LOWER PART OF SAID BED, STEAM INTRODUCED AT THATPOINT AND, AT A HIGHER LEVEL IN SAID BED, STEAM, COMBUSTION SUPPORTINGGAS AND GASEOUS COMBUSTION RESIDUES, CAUSING SAID BED IN ITS DOWNWARDTRAVEL TO PASS THROUGH THE INTERSTICES OF LARGE SIZE BODIES MAINTAINEDAS A PACK IN TWO SEPARATE ZONES IN THE PATH OF SAID BED, SAID PACKSPREVENTING BACK-MIXING OF THE FINELY DIVIDED SOLID UPARDLY THROUGH SAIDZONES INTO PRECEDING PORTIONS OF SAID BED, INTRODUCING THE COMBUSTIONSUPPORTING GAS INTO SAID BED BETWEEN SAID ZONES, RECOVERING FROM ABOVESAID BED VAPOROUS PRODUCTS OF THE CARBONIZATION OF SAID CARBONIZABLESOLID AND RECOVERING CARBONIZED SOLID FROM THE LOWER PORTION OF SAID BEDBELOW THE POINT OF INTRODUCTION OF STEAM INTO SAID BED, THE FLOW OFMATERIALS AND THE FEED OF STEAM AND COMBUSTION SUPPORTING GASES BEING SOREGULATED THAT THROUGHOUT THE UPPER PORTION OF THE BED ABOVE THE UPPERPACKED ZONE, THE FINELY DIVIDED MATERIAL IS MAINTAINED AT A CARBONIZAIONTEMPERATURE ABOVE THE PLASTIC RANGE OF SAID CARBONIZABLE SOLID ANDBETWEEN 900-1400* F., IN THE NEXT LOWER ZONE INCLUDING THE UPPER PACKEDZONE, THE FINELY DIVIDED MATERIAL IS MAINTAINED AT A TEMPERATURE BETWEENABOUT 1600-2000* F., AND IN THE LOWERMOST ZONE, INCLUDING THE LOWERPACKED ZONE, SAID MATERIAL IS QUENCHED WITH STEAM.